Actually you need to use ssl_dh=<
/usr/local/etc/dovecot/dh.pem

Note the <

Aki

-------- Original message --------
From: "Michael A. Peters" <mpeters@domblogger.net>
Date: 13/11/2018 05:44 (GMT+02:00)
To: dovecot@dovecot.org
Subject: Re: New install - getting error: "Failed to initialize SSL server context: Couldn't parse DH parameters"

try

openssl dhparam -out /usr/local/etc/dovecot/dh.pem 2048

On 11/12/2018 07:28 PM, James Brown wrote:
> I’m setting up Dovecot using Homebrew on a new server and am getting
> this when I try to login via IMAP:
>
> Nov 13 14:13:35 auth: Debug: auth client connected (pid=30719)
> Nov 13 14:13:35 imap-login: Info: Aborted login (no auth attempts in 0
> secs): user=<>, rip=::1, lip=::1, secured,
> session=<gM0HNIN6HtoAAAAAAAAAAAAAAAAAAAAB>
> Nov 13 14:18:33 auth: Debug: Loading modules from directory:
> /usr/local/Cellar/dovecot/2.3.2.1/lib/dovecot/auth
> Nov 13 14:18:33 auth: Debug: Module loaded:
> /usr/local/Cellar/dovecot/2.3.2.1/lib/dovecot/auth/lib20_auth_var_expand_crypt.so
> Nov 13 14:18:33 auth: Debug: Read auth token secret from
> /usr/local/var/run/dovecot/auth-token-secret.dat
> Nov 13 14:18:33 auth: Debug: auth client connected (pid=30848)
> Nov 13 14:18:33 imap-login: Error: Failed to initialize SSL server
> context: Couldn't parse DH parameters: error:0906D06C:PEM
> routines:PEM_read_bio:no start line: Expecting: DH PARAMETERS: user=<>,
> rip=::1, lip=::1, secured, session=<q7TJRYN6RdoAAAAAAAAAAAAAAAAAAAAB>
> Nov 13 14:18:33 imap-login: Info: Disconnected: TLS initialization
> failed. (no auth attempts in 0 secs): user=<>, rip=::1, lip=::1,
> secured, session=<q7TJRYN6RdoAAAAAAAAAAAAAAAAAAAAB>
>
> I’ve used:
>
> Openssl gendh 2048
>
> And put the output:
>
> -----BEGIN DH PARAMETERS-----
> MIIBCAKCAQEA0IF7kQX32IJFm/5HEVwYf7Be4G9iY86MvLiFLL3wHGqcPT3EMsIv
> YSe5XOT0Q7DGXPOZ+DLlJq8KDHxWKNI6j/0ZaRBrF38CWj8Jqxa8pqo9FVSWj45b
> JwSLqBSoBIEFWibqSE6L8wlV8xjMsB34xLHduJDNbaBzsooN749CopTkmkuGeXKH
> waOEbDzlOq+qHEa4bjx2/e/TnPj0kCrMnfeU4QILo1rJwuN4nY6k7fGwgEDVa2hE
> oOrVfJxxxxxxxxxyyyyyuuuixxxxblahblahblahhhkkkkkkkkkkkkXCGsxhlDQO
> QmzOhHqPovzbBByO9iR5fu3xbNm9YRxPowIBAg==
> -----END DH PARAMETERS——
>
> Into a file dh.pem and then added
>
> ssl_dh=/usr/local/etc/dovecot/dh.pem
>
> To my dovecot.conf file.
>
> Reloaded Dovecot but still get the same error.
>
> Any suggestions?
>
> macOS 10.13.6, Dovecot 2.3.2.1
>
> Any suggestions?
>
> Thanks,
>
> James.